Projector systems can turn any surface into a display surface. Integrated with interactivity mechanism, projector systems can turn any surface or space into an interactive surface or space, thus enabling interesting usage models. There has been research and development in this area of interactive projector systems. Reducing system power of projector systems is and will become more important when it comes to the production of these projector systems. For some projector systems, there are three main components: a light source, an imager, and projection optics. The imager may be a micro-display and its power consumption is usually very small in the range of tens or hundreds of milliwatts. The light source is typically the biggest power consumer in the projection system and utilizes a larger portion of system space for thermal management. Some projector systems use traditional lamps. To improve the light source efficiency, light emitting diode (LEDs) technology is often used instead of traditional lamps, especially Red-Green-Blue (RGB) LEDs. RGB LEDs can help eliminate the color wheel or dichroic mirror/prisms used in the projector system. Currently for LED based projector systems, the light source power consumption is roughly 1 W for 10 lumens. More efficient light sources such as hybrid light source or laser light source are being developed. Some light source power saving technologies focus on improving the light source efficiency. In current projection systems, the light source is usually always fully on. In some projector systems with high lumens a brightness adjustment of the light source may be made based on ambient light. In this case an ambient light sensor can be used to detect the ambient light intensity to adjust the projector brightness based on the ambient light measured by the ambient light sensor.